rgw: ignore exit status when removing base apache dir
rgw: ignore exit status when removing base apache dir

subdirs have already been removed, and this only needs to succeed once
per host.

Signed-off-by: Josh Durgin <51652c783f70f5b272ebd02f1fd20d3af7a2449f@inktank.com>

ivotron/teuthology,tchaikov/teuthology,t-miyamae/teuthology,robbat2/teuthology,t-miyamae/teuthology,yghannam/teuthology,ktdreyer/teuthology,ceph/teuthology,zhouyuan/teuthology,dreamhost/teuthology,caibo2014/teuthology,SUSE/teuthology,dmick/teuthology,SUSE/teuthology,michaelsevilla/teuthology,ivotron/teuthology,zhouyuan/teuthology,michaelsevilla/teuthology,dmick/teuthology,caibo2014/teuthology,yghannam/teuthology,dmick/teuthology,SUSE/teuthology,dreamhost/teuthology,ceph/teuthology,ktdreyer/teuthology,robbat2/teuthology,tchaikov/teuthology